What is the integral in calculus? Discuss the concept of limit in detail.

What is the Integral in Calculus? Explained with Calculations

In calculus, an integral is a mathematical tool that measures the accumulation or total of a quantity, often represented as the area under a curve on a graph. It plays a central role in analyzing continuous change and enables the precise calculation of areas, volumes, and a wide range of mathematical and scientific applications.

Integrals are categorized into definite and indefinite forms, each serving unique purposes in mathematical modeling and problem solving. For solving problems in engineering, economics, physics, and many other fields, making it an essential tool in mathematical modeling and problem solving the concept of the integral is used.

In this article, we will explore the concept of integral in Calculus with the help of definitions, Categories, and laws of integral in calculus. Moreover, with the help of detailed examples and answer integral in calculus explain.


An integral in calculus is a mathematical operation that calculates the accumulated total of a quantity, often represented as the area under a curve on a graph. It serves as a fundamental tool for measuring and analyzing the continuous change in various fields of science and engineering.

Integral in calculus: Types

In calculus, there are two primary categories of integrals:

·       Definite Integral:

The definite integral is used to calculate the exact accumulated total of a quantity between two specific points on a function's curve. It yields a single numeric value and represents the net area between the curve and the x-axis over a defined interval.

·       Indefinite Integral:

The indefinite integral, often referred to as an antiderivative, calculates a family of functions that, when differentiated, yield a given function. It includes a constant of integration (C) and represents a broader class of functions.

Laws of Integral in Calculus

In calculus, several fundamental laws and properties run the manipulation of integrals. Here are some of the key laws and properties of integrals:

·       Linearity of Integration:

In linear terms of integration, the answer to the sum function integral is always equal to the individual function. In other words, If a and b are constants and two functions are f(x) and g(x):

  ∫(af(x)+bg(x)) dx =   a∫ f(x)dx +b∫ g(x)) dx

·       Constant Multiple Rule:

You can factor constants out of an integral:

  ∫(af(x) dx =   a ∫f(x) dx 

·       Addition/Subtraction Rule

  ∫(f(x)-g(x)) dx =   ∫ f(x)dx - ∫ g(x)) dx

This shows that of two functions integral answer is equal to their integral difference.

·       Power Rule for Integration

The integral of xn concerning x is (n+1)-1x(n+1) for all real numbers n ≠ -1.

·       Integration of Constants:

The integral of a constant is equal to the constant times the variable of integration:

     ∫ a dx = ax + C

C= integration constant

·       Substitution: Integration

This technique allows you to simplify an integral by making a substitution, often involving u-substitution.

·       Integration by Parts:

Integration by parts is a method for integrating the product of two functions. It is based on the formula:

udv = uv - vdu

·       Definite Integral Properties:

The definite integral has properties such as the Fundamental Theorem of Calculus, which relates definite integrals to antiderivatives, and the Mean Value Theorem for Integrals, which guarantees the existence of an average value of a function over an interval.

·       Change of Limits:

When changing the limits of integration, you need to account for the effects on the integral. This is important when performing substitutions or transformations.

·       Symmetry Properties:

Some functions exhibit symmetry, which can simplify integration. For example, even functions have symmetry about the y-axis, while odd functions have symmetry about the origin.


Example 1:

Suppose (2x2+5x-1) dx simplifies the given expression.


Given data

(2x2+5x-1) dx

Now we solve step-by-step

Step 1: Take the integral of the constant integral.

∫ 2x2dx=2∫x2dx

The integral of xn is xn+1/n+1 when n≠−1:

∫ x2dx= 2x3/3

Step 2: Again take the integral of the constant integral.

∫ 5xdx=5∫x dx

Take integration we get

∫ x dx= 5x2/2

Step 3:

∫ (−1) dx=−x

Step 4:

Combine all the given results. Then we get.

(2x2+5x-1) dx =>  2x3/3 +5x2/2−x +C

For better understanding simplify the expression

(2x2+5x-1) dx = x(4x2+15x−6)/6+C

You can use online calculators like the Integral calculator offered by MeraCalculator to solve the problems of integration to get rid of lengthy calculations.

Example 2:

94 (9x2-3x+10) dx solve the given integral.


Given data

94 (9x2-3x+10) dx

Step 1: Take integration and then put the value of the upper and lower bound.

94 (9x2-3x+10) dx => 94 (9x2) dx - 94 (3x) dx +94 (10) dx

Step 2: Take the value of constant out of the integration  

94 (9x2-3x+10) dx => 9 94 (x2) dx – 3 94 (x) dx +10 94 (1) dx

Step 3: Now take the integration of the given function. We get the result.

94 (9x2-3x+10) dx =9 94 (x2) dx – 3 94 (x) dx +10 94 (1) dx

94 (9x2-3x+10) dx =|3x3−3x2/2+10x|94

Step 4: Now put the value of the upper and lower bound we get.

94 (9x2-3x+10) dx = (3(9)3−3(9)2/2+10(9)) −(3(4)3−3(4)2/2+10(4))

Step 5:

Now simplify the result

94 (9x2-3x+10) dx = (4311/2) −(208)

94 (9x2-3x+10) dx = 3895/2

94 (9x2-3x+10) dx = 1947.5


In this article, we have discussed the definitions, Categorization, and laws of integral in calculus. Also, for better understanding we have discussed in this article examples of integral and their solution. After studying this article anyone can easily defend this article.


Question# 1:

How does integration relate to differentiation?


Differentiation and integration are inverse operations in calculus. If you find the derivative of a function, you can often find its original function by integrating the derivative.

Question# 2:

What are some common applications of integrals?


Integrals are used to calculate areas under curves, volumes of solids, work done by forces, accumulation of quantities over time, and in solving differential equations, among other applications.

Question# 3:

Are there any techniques to simplify integration?


Yes, techniques such as integration by substitution and integration by parts can simplify complex integrals. Recognizing patterns in functions can also make integration more manageable.

Courtesy : CBSE